Techs are actually pretty effective in Ep 4. But the main reason they aren't suggested in Ep 1 in 2 is that techs aren't as effective. There's this glitch(?) called Damage Cancel(DMC for short), which is present in most versions of PSO, where if you and someone else damage something at the same time, one of the damages will be cancelled, usually the lower one. Techs are especially bad at this since a lot them are AOE and therefore can damage cancel a lot. It's fine to use techs if you're in a solo party, but just keep in mine usually spamming techs in a party just ends up making things harder and longer than they need to be. Also, tech damage just kind of sucks in Ultimate for most of Ep 2.